When two bodies, particularly of unlike materials, are brought together into intimate contact, a redistribution of electrons across the interface is likely to occur. An attractive force is established as equilibrium is achieved. Work must be done in opposition to these attractive forces if and when the bodies are separated. The energy so expended manifests itself as an increase in electrical tension or voltage between the respective surfaces, which become electrically charged with respect to each other. If a conductive path is available, the charges thus separated will reunite immediately. If no such path is available, as in the case of nonconductors, the potential increase with separation may reach values of several thousand volts. The generation of such electrical forces by contact is known as triboelectricity.
The charge on a charged object will be located on the exterior surface thereof, and these forces have a strong influence on nearby objects. If a neighboring object is a conductor it will experience a separation of charges by induction. Its repelled charge is free to give or receive electrons as the case may be; if another conductor is brought near, the transfer may occur through the agency of the spark, very often an energetic spark.
Triboelectrically generated charges may adversely affect or even electronically destroy a number of electronic circuits or solid state devices sensitive to sudden or stray electric charges or static electricity. Micro-circuit devices such as integrated circuit chips may be destroyed or weakened by electrostatic discharge prior to their incorporation into the electrical or electronic equipment for which they were designed. Damage from electrostatic discharge may make such devices prone to latent or catastrophic failure during use
To prevent electrostatic breakdown, containers in which such devices are stored and transported have been provided with means for short circuiting the device terminals or pins. This short circuiting serves to prevent the accumulation of potentially damaging static charges on the device.
U.S. Pat. No. 4,171,049 discusses the utilization of a series of conductive slots or grooves in which solid state devices may be inserted and later dispensed to manufacturing equipment.
Other containers have been developed for portable use as for example in the device replacement market. These are typically small box like containers that house conductive sponge or foam sheets into which the device terminals are temporarily imbedded. An example is found in U.S. Pat. No. 4,333,565.
Another means well known in the art for providing protection of solid state devices is the use of carbon black or carbon powder in varying amounts in the material forming the container for the solid state devices.
U.S. Pat. No. 4,494,651 issued to Malcolm discloses a portable work station in which electrically conductive material, such as carbon black particles, aluminum particles, and metal filings, is blended with thermoplastic material to make an electrically conductive case.
While much attention has been directed to the provision of conductive or antistatic containers, or containers with a combination of such properties for the storage of devices sensitive to electrostatic discharge, a corresponding need is present for ancillary equipment and materials which do not negate the advantages obtained by the use of the special containers discussed above.
Documentation in the form of conventional sheets of paper, and other written matter, is frequently associated with the production, of electrically sensitive hardware and components thereof, such as computer equipment and circuit boards. A conventional notebook binder used to store or compile such written materials typically has a broad surface, and is sometimes subject to the same triboelectric defects discussed earlier.
In many special environments such as clean room environments in the computer component industry and other industries, documentation in the form of data sheets, progress reports, and the like is desirably compiled in some form of notebook in order to meet standard operating practice for recording data, keeping track of production runs, order data, and the like.
In each case, it is desirable to house such documentation in a binder which will not present the risk of the generation of an electrostatic discharge, and the destruction or impairment of electrostatically sensitive components near the binder.
It is therefore an object of the present invention to provide a notebook binder which has either a conductive or an antistatic surface to reduce or eliminate the possibility of inadvertent and undesirable electrostatic discharge into the working environment.
It is also an object of the present invention to make a binder that has been blow-molded, preferably in a double-wall configuration, to provide resistance to mechanical abuse during normal usage.